JP4500603B2 - Road surface freezeability index calculation system, road surface freezeability index calculation method, and road surface freezeability index calculation program - Google Patents

Description

  The present invention relates to a road surface freezeability index calculation system, a road surface freezeability index calculation method, and a road surface freezeability index calculation program for calculating road surface freezing possibility.

Predicting road surface freezing has been widely performed. Specific road surface freeze prediction methods include road surface information data determined by the type of road surface, such as altitude, roughness length, albeto (reflectivity), and evaporation rate, as well as weather and cloudiness measured in the vicinity of the road surface freeze prediction target point. , Air temperature, pressure, wind direction, wind speed, precipitation (snow) amount, net radiation amount, and other weather information data, and the road surface temperature predicted by applying the heat balance model, dry, wet, compressed snow, freezing, etc. A method of predicting road surface freezing using moisture data indicating the presence or absence of moisture on the road surface is used. Moreover, in the technique described in Patent Document 1, road surface freezing is predicted using topographic information including an integral value and altitude of daily solar radiation.
JP 09-114371 A

  In the above road surface freezing prediction method, road surface freezing can be predicted by applying daily-changing data such as weather information, presence / absence of moisture, and amount of solar radiation to data unique to each point such as road surface information and topographic information. it can. Since freezing depends on weather conditions, it is impossible to predict freezing unless the influence of weather conditions is taken into consideration. However, in reality, the road surface and surrounding conditions vary greatly, and there are differences in the ease of freezing depending on the road, and a method of expressing the ease of freezing has been an issue.

  The present invention has been made in view of the above problems, and its purpose is to calculate a road surface freezeability index calculation system that makes it possible to calculate a road surface freezing index that indicates how easily the road surface is frozen, The object is to provide a road surface freezing index calculation method and a road surface freezing index calculation program.

The present invention for solving the above problems is an all-sky camera that is installed on a moving body that moves on a road and shoots an all-sky image, road surface temperature acquisition means that acquires a road surface temperature for each point of the road, and Based on imaging data captured by the all-sky camera, irradiance time data acquisition means for acquiring irradiance time data indicating the time when the sunlight rays reach the road surface for each point of the road, and the road surface temperature acquisition means The road surface freezing index indicating the freezing possibility of the road surface is calculated for each point of the road based on the road surface temperature acquired by the above and the time when the sunlight reaches the road surface indicated by the illuminating time data. seen including a road freezable index calculation means, and wherein the imaging data, position data indicating the captured position is associated, the adjustable-irradiation time data acquisition means, based on the positional data sun Gets the road, the based on the imaging data and the sun path, the friendly calculates the irradiation time data, characterized in that.

  By doing in this way, since the road surface freezing possibility index showing the freezing possibility of a road surface can be calculated, the road surface freezing possibility index showing how easy the road surface freezes can be calculated.

  Further, in the road surface freezing possibility index calculating system, the road surface freezing possibility index calculating means calculates a road surface freezing possibility index in the road surface of each point of the road, and the road surface freezing possibility index is calculated as each point. Road surface freezing possibility index display means for displaying in association with each other may be further included. In this way, since it is possible to calculate and display a road surface freezing index indicating road freezing potential for each point on the road, it is possible to know which point on the road is likely to freeze, You can be careful when driving on the road.

In addition, the road surface freezing index calculation method according to the present invention is based on imaging data that is installed on a moving body that moves on a road and captures an all-sky image, so that sunlight rays reach the road surface directly. The irradiating time data indicating the time to perform is acquired in the irradiating time data acquiring step for acquiring each road point, the road surface temperature acquiring step for acquiring the road surface temperature for each point of the road, and the road surface temperature acquiring step. Road surface freezing that calculates a road surface freezing index indicating the freezing possibility of the road surface based on the road surface temperature and the time when the sunlight reaches the road surface indicated by the illuminating time data for each point of the road see containing possibilities and index calculation step, a, wherein the imaging data, position data indicating the captured position is associated, the adjustable-irradiation time data acquisition step, the positions de Obtaining a sun path on the basis of data, the based on the imaging data and the sun path, and calculating the friendly irradiation time data, it is characterized.

In addition, the program according to the present invention is an illuminating device that indicates the time when the sun rays reach the road surface based on imaging data that is installed on a moving body that moves on a road and that is imaged by an all-sky camera that captures all-sky images. Visible time data acquisition means for acquiring time data for each point of the road, road surface temperature acquisition means for acquiring road surface temperature for each point of the road, and road surface temperature acquired by the road surface temperature acquisition means, Road surface freezing index calculating means for calculating a road surface freezing index indicating the freezing potential of the road surface based on the time when the sunlight rays reach the road surface indicated by the lightable time data, for each point of the road, cause the computer to function, wherein the imaging data, position data indicating the captured position is associated, the adjustable-irradiation time data acquisition means, based on the positional data sun Gets the road, the based on the imaging data and the sun path, the friendly calculates the irradiation time data, characterized in that.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a road surface freezing index calculation system 1 according to the present embodiment. For the road surface freezing possibility index calculation system 1, for example, a computer similar to a known personal computer or server computer can be used. CPU 10, RAM 12, input / output unit 14, communication unit 16, database 18, external storage medium 20, a hard disk 22, a display unit 24, an input unit 26, and a bus 28. The CPU 10, RAM 12, and input / output unit 14 are connected to each other via a bus 28, and the input / output unit 14 is connected to the communication unit 16, the database 18, the external storage medium 20, and the hard disk 22.

  The CPU 10 controls each part of the road surface freezing index calculation system 1 and performs various calculations. For example, the CPU 10 also calculates a road surface freezing index calculation described later. The RAM 12 operates as a work memory for the CPU 10. The RAM 12 holds programs and parameters related to various processes performed by the CPU 10. The input / output unit 14 relays data transmission / reception between the CPU 10, the communication unit 16, the database 18, the external storage medium 20, and the hard disk 22. Further, the communication unit 16, the database 18, the external storage medium 20, and the hard disk 22 are controlled according to instructions from the CPU 10. A conventionally known hard disk can be used as the hard disk 22 and stores computer programs and data. A program according to the present invention is also stored. As the external storage medium 20, any computer-readable information storage medium such as a flexible disk, a CD-ROM, a CD-RW, a DVD-RAM, a USB flash memory, a ROM card, and a removable hard disk can be used. And memorize data. A program according to the present invention is also stored. The database 18 stores lighting time data and road surface temperature data, which will be described later, and stores a calculated road surface freezing index. The display unit 24 is a display unit such as a display, and performs display in accordance with an instruction from the CPU 10 to the user of the road surface freezing index calculation system 1. The input unit 26 is an input unit such as a keyboard or a mouse, and receives an input by a user operation of the road surface freezing index calculation system 1 and outputs it to the CPU 10.

  FIG. 2 is a functional block diagram of the road surface freezing possibility index calculation system 1 according to the present embodiment. Functionally, the road surface freezing index calculating system 1 functionally includes an irradiating time acquiring unit 30, a road surface temperature acquiring unit 32, a drying time acquiring unit 34, a road surface freezing index calculating unit 36, and a road surface freezing index calculating display. A portion 38 is included.

  The erasable time acquisition unit 30 calculates and acquires erasable time data indicating the erasable time for each point. Irradiable time data means that the sun rays directly reach the road surface without being obstructed by the buildings and trees, etc. that exist on the side of the road, by performing observations as described below. It is possible to acquire the time for each season, and to digitize the time.

  It is preferable to use an observation vehicle 50 as shown in FIG. 3 in order for the illuminable time acquisition unit 30 to calculate the illuminable time. In the observation vehicle 50, a GPS antenna 52 for grasping the position of the own vehicle, a video camera 54 with a fisheye lens for photographing a whole sky image around the vehicle, and a temperature for measuring the temperature are shown in FIG. Temperature sensor 55 and a road surface temperature sensor 56 for measuring the road surface temperature are installed.

  FIG. 4 is a hardware configuration diagram of the observation vehicle 50. In the observation vehicle 50, a computer 60, a GPS logger 70, a back lamp 82, a vehicle speed detection circuit 84, a thermometer 86, a radiation thermometer 88, an all-sky camera 90, and a digital video camera 92 are installed. The thermometer 86 constitutes the temperature sensor 55, the radiation thermometer 88 constitutes the road surface temperature sensor 56, and the all-sky camera 90 and the digital video camera 92 constitute the fish camera-equipped video camera 54.

  A computer similar to a conventionally known personal computer can be used as the computer 60, and the computer 60 includes a control unit 62, a communication unit 64, and a storage unit 66. The control unit 62 controls each unit of the computer 60, and also stores information input from each device in the storage unit 66 and calculates a solar radiation shielding amount from the stored information as described below. The communication unit 64 is connected to the GPS logger 70, the all-sky camera 90, and the digital video camera 92 so that data can be transmitted and received. Further, the control unit 62 may be configured to control the GPS logger 70, the all-sky camera 90, and the digital video camera 92.

  The GPS logger 70 can be the same as a conventionally known GPS logger. The GPS logger 70 includes a control unit 72, a storage unit 74, a GPS antenna 76, a gyro sensor 78, and a communication unit 80. Is done. The communication unit 80 is connected to the back lamp 82, the vehicle speed detection circuit 84, the thermometer 86, the radiation thermometer 88, and the computer 60 so that data can be transmitted and received. In addition, the control unit 72 controls each unit of the GPS logger 70 and also performs processing of storing signals input from the GPS antenna 76, the gyro sensor 78, and the communication unit 80 in association with each other in the storage unit 74. Further, in accordance with an instruction from the computer 60, processing for reading data stored in the storage unit 74 and transmitting it to the computer 60 is also performed. Further, the controller 72 can be configured to control the thermometer 86 and the radiation thermometer 88.

  The GPS antenna 76 can be the same as a conventionally known GPS antenna that constitutes the GPS antenna 52. When the GPS antenna 76 receives a signal from a GPS satellite, the GPS logger 70 is connected to the observation vehicle 50. Position, orientation and speed of That is, latitude / longitude / altitude data (position data) indicating the latitude / longitude / altitude of the position where the observation vehicle 50 exists, azimuth data indicating the azimuth (direction in which the observation vehicle 50 is directed), and the earth of the observation vehicle 50 on the earth Get speed data indicating the speed at.

  The back lamp 82 is a back lamp provided in a normal vehicle and lights up when the observation vehicle 50 moves backward. Then, the GPS logger 70 receives information about whether or not the back lamp 82 is lit, and determines that the observation vehicle 50 is moving backward when it is lit. The vehicle speed detection circuit 84 is a circuit that detects the vehicle speed of the observation vehicle 50 provided in the normal vehicle, and outputs the vehicle speed of the observation vehicle 50 as numerical data. The GPS logger 70 receives the numerical data, and acquires movement speed data indicating the movement speed of the observation vehicle 50. The gyro sensor 78 may be the same as a conventionally known gyro sensor, and the gyro sensor 78 outputs the angular velocity of the observation vehicle 50 with respect to three axes orthogonal to each other. The GPS logger 70 acquires angular velocity data indicating the angular velocity of the three axes from the gyro sensor 78. If the GPS antenna 76 cannot receive a signal from a GPS satellite, the mobility from the final position / orientation / velocity data obtained from the signal from the GPS antenna 76 is determined as backward information, moving speed data, angular velocity. Based on the data, position data indicating the position where the observation vehicle 50 exists, direction data indicating the direction in which the observation vehicle 50 faces, and speed data indicating the speed of the observation vehicle 50 on the earth are acquired.

  A thermometer 86 similar to a conventionally known thermometer can be used, and the thermometer 86 measures the outside temperature of the observation vehicle 50 and outputs temperature data indicating the outside temperature to the GPS logger. The radiation thermometer 88 can be the same as a conventionally known radiation thermometer, and the radiation thermometer 88 measures the surface temperature of the road surface by measuring infrared radiation from the road surface. Road surface temperature data indicating the surface temperature of the road surface is output to the GPS logger 70.

  The control unit 72 acquires the position data, azimuth data, speed data, temperature data, road surface temperature data, the date and time when each of these data was acquired, or the observation date and time when each data was observed, acquired as described above. Data is stored in association with the storage unit 74. That is, each data is always observed during observation, and the simultaneously acquired data can be stored in association with each other. The observation date / time data and each of the data may be stored in association with each other.

  Next, as shown in FIG. 3, the all-sky camera 90 is installed on the roof portion of the observation vehicle 50 with the imaging unit facing upward in the observation vehicle 50. That is, the all-sky camera 90 performs all-sky shooting in the upward direction of the observation vehicle 50. The omnidirectional camera 90 can be the same as a conventionally known omnidirectional camera, but the circumference designed to capture a semicircular field of view particularly with an angle of view of 180 degrees or more. It is desirable to use a fisheye lens. Then, the all-sky camera 90 outputs imaging data as an imaging result to the computer 60 or the digital video camera 92. The imaging results of the all-sky camera 90 will be described below.

  First, the case where the observation vehicle 50 exists in a position as shown in FIG. 5 will be described. That is, the observation vehicle 50 exists at the point 104 on the road 100, and the building 102 exists on the side of the road. While the observation vehicle 50 moves on the road 100, it acquires solar radiation shielding amount data at several points.

  In this way, when the image is captured by the omnidirectional camera 90 in a situation where the building 102 exists on the side of the road, a circular imaging result (sky map) as shown in FIG. 6 is obtained. That is, in the imaging result, the circumference of the circle is a photograph of the lens surface of the all-sky camera 90, and the center of the circle is a photograph of the direction in which the lens is facing. By photographing in this way, the result is that the building 102 is reflected in a part of the circle. In other words, a building or a solar shading object such as a tree around the point 104 appears in the imaging result.

  The imaging data is also constantly observed during observation, and is recorded in the digital video camera 92 as a moving image by recording with the digital video camera 92. Alternatively, it may be stored in the storage unit 66 of the computer 60. The imaging data is also stored in association with imaging date / time data indicating the date / time when the imaging data was stored or the date / time when the imaging data was stored, and the imaging data and the GPS logger are determined by the imaging date / time data and the observation date / time data. The position data, azimuth data, speed data, air temperature data, and road surface temperature data stored in 70 are associated with each other.

  And the control part 62 calculates the amount of solar radiation shielding based on the imaging data acquired as mentioned above, and the solar orbit determined by the revolution degree and rotation motion of the earth. This calculation process will be described in detail below.

First, the time angle t, altitude angle h, and azimuth angle A of the solar orbit are based on latitude φ, longitude λ, time H, solar declination δ, and time difference ET, using the following formulas (1) and (2). And Equation (3). The solar declination δ and the time difference ET vary depending on the date.
t = λ−9 + ET + (H−12) (1)
sinh = sinφsinδ + cosφcosδcost (2)
sinA = −cosδsint / cosh (3)

  As described above, the altitude angle h and the azimuth angle A of the sun are different values based on the latitude / longitude / date and time of the measurement point. The control unit 62 observes the date and time in a range that can be regarded as the same date and time as the date and time indicated by the imaging date and time data in the imaging data stored in the storage unit 66 or the digital video camera 92 in association with the imaging time data. The position data and direction data stored in the storage unit 74 in association with the date / time data are read out. In this way, the latitude / longitude / altitude of the place where the image data was imaged and the direction of the observation vehicle 50 when the image was captured can be acquired.

  When the latitude / longitude / elevation of the point where the imaged data is imaged can be acquired in this way, the position of the sun for each date and time at the point is acquired by Equation (1), Equation (2), and Equation (3). be able to. An example in which the position is plotted on the imaging data is shown in FIG. The solar orbit becomes a line when connecting the points plotted every day, and in FIG. 7, the solar orbit for each month is shown as a line. The solar orbit 110 represents the January 1, the solar orbit 112 represents the April 1, and the solar orbit 114 represents the July 1 solar orbit. The imaging data does not normally change from day to day, but the sun orbit draws a different line every day in this way on the imaging data. In this process, since the solar orbit varies depending on the altitude, the altitude correction at the measurement point and the altitude correction of the solar radiation shielding object are performed according to the altitude of the measurement point indicated by the position data. Furthermore, the direction correction which rotates imaging data is also performed according to the direction of the observation vehicle 50 shown by direction data.

  And the control part 62 calculates the time (sunlight irradiation time) when a sunlight ray is not obstruct | occluded by the solar radiation obstruction | occlusion like the building 102 in a solar orbit in imaging data. Specifically, for example, by acquiring solar orbit shielding data as shown in FIG. FIG. 8 shows whether or not there is an obstruction on the solar orbit on a road and month and day, with the vertical axis as the distance from the reference point and the horizontal axis as the time. It is a graph. The graph displays black when there is an obstruction on the solar orbit and white when there is no obstruction. Each becomes solar orbit shielding data representing the presence or absence of shielding of the sun orbit for each point and hour. And the white time for every point becomes the illuminating time of the sunlight at the point.

  In this way, it is possible to calculate the sunshine illumination time for each latitude / longitude / altitude / month / day at the point where the observation vehicle 50 has carried out the observation travel, and the illumination time acquisition unit 30 is able to calculate the illumination time. Acquire time as reproducible time data. In addition, the direct time rate which shows the rate which sunlight reaches | attains a road surface without being interrupted by a shield for one day can also be used for the lightable time data, for example. The calculation of the sunlight irradiation time may be performed by a computer provided separately, for example, based on each data acquired by the observation vehicle 50.

  Next, the road surface temperature acquisition unit 32 acquires road surface temperature data indicating the road surface temperature for each point. As the road surface temperature data, the road surface temperature data measured as described above by the road surface temperature sensor 56 provided in the observation vehicle 50 can be used. That is, by obtaining road surface temperature data measured by the observation vehicle 50 and stored in the storage unit 74 in association with the latitude / longitude / altitude / month / day corresponding to the visible time, The road surface temperature corresponding to the lightable time can be acquired for each point.

  As described above, the road surface freezing possibility index calculating unit 36 is based on the irradiable time data acquired by the irradiable time acquiring unit 30 and the road surface temperature data acquired by the road surface temperature acquiring unit 32. Calculate the freezing potential index. In this calculation, the possibility of freezing is calculated based on the road surface temperature and the illuminating time, using the property of the road surface that the possibility of freezing is higher as the road surface temperature is lower and the possibility of freezing is lower as the lighting time is longer. An index is calculated.

In a certain road, when the road surface temperature at a point x from the starting point is a (x) and the illuminating time is b (x), the road surface freezing possibility index g (x) is expressed by the following equation (4). Can be represented. However, when calculating the road surface freezing possibility index for the purpose of clarifying the road surface freezing possibility point in the road surface freezing possibility calculation target section of a road, a (x) and b (x) are The calculation may be performed by normalizing the maximum value of the a (x) and the b (x) from the start point to the end point of the road surface freezing possibility calculation target section as 1 and the minimum value as 0, respectively.
g (x) = m × a (x) + n × b (x) (4)

  Here, m and n are weighting factors indicating the weight of the irradiating time and the road surface temperature with respect to the road surface freezing index. The m and n can be obtained by measuring the time until the road surface dries for each point under various road surface temperatures and lighting times. That is, for example, on a road surface with poor drainage, the time until drying may be long. In addition, for example, due to spring water, the time until drying may be longer. In addition, for example, roads with heavy traffic may dry quickly. In such cases, the road surface freezing index should be calculated more accurately by experimentally measuring the relationship between the irradiance time and road surface temperature and the road surface freezing index for each point. Will be able to.

  The drying time acquisition unit 34 acquires the result of measuring the time until the road surface is dried for each combination of the illuminating time and the road surface temperature, and calculates the weighting factors m and n. Of course, m = n = 1 may be used for the calculation of the road surface where there is no water supply other than the water supply due to rain and snow, and the road surface where the traffic volume is not so high.

  And the road surface freezing possibility index display part 38 displays the road surface freezing possibility index | exponent for every point calculated in this way on the display part 24 of the road surface freezing possibility index calculation system 1, for example. This is notified to the user of the road surface freezing index calculation system 1. At the time of display, it is desirable to display a specific point in association with a road surface freezing possibility index at the specific point. FIG. 9 shows an example of the specific display.

  In FIG. 9, a map display unit 130, a road surface freezing index display unit 132, and a legend display unit 134 are provided. The map display unit 130 displays a map and displays a road 120 as one element of the map. In FIG. 9, the right end of the figure is set to a 0 km point, and the distance is displayed as 1 km, 2 km,... According to the actual distance of the road 120 as it proceeds in the left direction. In FIG. 9, the right side of the figure is the starting point (0 km), but the left side may be the starting point, or the road surface freezing index display unit 132 may be provided vertically, and the upper or lower part of the drawing may be the starting point. Of course.

  Then, the road surface freezing index display unit 132 displays the road surface freezing index 124 of points on the road 120 corresponding to each distance (each point) with the distance corresponding to the distance display from the right end as an axis. . The road surface freezing possibility index 124, as shown in the legend display section 134, displays that the road surface freezing possibility index increases, that is, the road surface is easy to freeze as the color becomes darker. Yes.

  In this way, by calculating the road surface freezing possibility index indicating how easily the road surface is frozen, and displaying the index for each day according to each point on the road, It is possible to know the road surface that is easily frozen, and to alert the passerby. Furthermore, by taking the average of the road surface freezing potential index for each month and day, it is possible to indicate how easily the road surface is frozen throughout the year by the road surface freezing potential index.

  In calculating the lighting time, the lighting time may be changed according to the prediction of the sunshine time indicated by the weather forecast. In this way, in addition to the road surface freezing index corresponding to the nature of the road itself, it is possible to calculate a road surface freezing index corresponding to the weather forecast. The road surface temperature is not only the actual measured value, but also the national land numerical data such as 1 km elevation data and land use data, the GPV data announced by the Japan Meteorological Agency (RSM) and forecast guidance, seawater temperature data and snow Acquire climatic data such as line elevation data and a direct rate for each point of the road, which is the ratio that the solar radiation is not obstructed by the buildings and trees, etc. that exist on the side of the road. If the predicted value of the road surface temperature obtained by applying the converted solar radiation shielding data and the traffic data for each point on the road to the heat balance model is used as the road surface temperature data, the characteristics of the road itself In addition to the road surface freezing index corresponding to the above, it is possible to calculate a road surface freezing index corresponding to the road surface temperature prediction.

It is a hardware block diagram of the road surface freezing possibility index calculation system concerning an embodiment of the invention. It is a functional block diagram of the road surface freezing possibility index calculation system concerning an embodiment of the invention. 1 is an external view of an observation vehicle according to an embodiment of the present invention. It is a functional block diagram of the observation vehicle concerning an embodiment of the invention. It is a bird's-eye view of the road concerning an embodiment of the invention. It is imaging data concerning an embodiment of the invention. It is the imaging data which described the solar orbit concerning embodiment of this invention. It is a graph of the solar orbit shielding data for every point and hour concerning the embodiment of the present invention. It is an example of a display of a road surface freezing possibility index concerning an embodiment of the invention.

Explanation of symbols

  1 Road surface freezing possibility index calculation system, 10 CPU, 12 RAM, 14 input / output unit, 16, 64, 80 communication unit, 18 database, 20 external storage medium, 22 hard disk, 24 display unit, 26 input unit, 28 bus, 30 Visible Time Acquisition Unit, 32 Road Surface Temperature Acquisition Unit, 34 Drying Time Acquisition Unit, 36 Road Surface Freezing Potential Index Calculation Unit, 38 Road Surface Freezing Potential Index Display Unit, 50 Observation Car, 52 GPS Antenna, 54 Video Camera with Fisheye Lens , 55 temperature sensor, 56 road surface temperature sensor, 60 computer, 62, 72 control unit, 66, 74 storage unit, 70 GPS logger, 76 GPS antenna, 78 gyro sensor, 82 back lamp, 84 vehicle speed detection circuit, 86 thermometer, 88 Radiation thermometer, 90 all-sky camera, 92 digital video camera.

Claims (4)

An all-sky camera that is installed on a moving body moving on the road and shoots a whole sky image;
Road surface temperature acquisition means for acquiring the road surface temperature for each point of the road;
Based on imaging data imaged by the all-sky camera, irradiance time data acquisition means for acquiring irradiance time data indicating the time when the sun rays reach the road surface for each point of the road;
Based on the road surface temperature acquired by the road surface temperature acquisition means and the time when the sun rays reach the road surface indicated by the observable time data, a road surface freezing index indicating the freezing possibility of the road surface is calculated based on the road surface temperature. Road surface freezing possibility index calculating means to calculate for each point,
Only including,
The image data is associated with position data indicating the imaged position,
The illuminable time data acquisition means acquires a solar orbit based on the position data, and calculates the illuminable time data based on the imaging data and the solar orbit,
A road surface freezing index calculation system characterized by that. In the road surface freezing possibility index calculation system according to claim 1 ,
The road surface freezing possibility index calculating means calculates a road surface freezing possibility index in the road surface of each point of the road,
Road surface freezing index display means for displaying the road surface freezing index in association with each point;
The road surface freezing possibility index calculation system characterized by further including. Based on imaging data that is installed on a moving body that moves on the road and captures an all-sky image, irradiance time data indicating the time when the sun rays reach the road surface is obtained for each point on the road. A visible time data acquisition step acquired at
A road surface temperature acquisition step of acquiring a road surface temperature for each point of the road;
Based on the road surface temperature acquired in the road surface temperature acquisition step and the time when the sunlight rays reach the road surface indicated by the illuminating time data, a road surface freezing index indicating the freezing possibility of the road surface is calculated based on the road surface temperature. and the road surface freezing possibility index calculation step of calculating for each point, only including,
The image data is associated with position data indicating the imaged position,
The illuminating time data acquisition step includes a step of acquiring a solar orbit based on the position data, and a step of calculating the irradiating time data based on the imaging data and the solar orbit.
The road surface freezing possibility index calculation method characterized by this. Based on imaging data that is installed on a moving body that moves on the road and captures an all-sky image, irradiance time data indicating the time when the sun rays reach the road surface is obtained for each point on the road. Irradiance time data acquisition means to acquire,
Based on the road surface temperature acquisition means for acquiring the road surface temperature for each point of the road, and the road surface temperature acquired by the road surface temperature acquisition means, and the time when the sunlight reaches the road surface indicated by the illuminating time data directly Causing the computer to function as a road surface freezing potential index calculating means for calculating a road surface freezing potential index representing the road surface freezing potential for each point of the road ,
The image data is associated with position data indicating the imaged position,
The illuminable time data acquisition means acquires a solar orbit based on the position data, and calculates the illuminable time data based on the imaging data and the solar orbit,
A road surface freezing index calculation program characterized by that.

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